Pneumatic tires consist of various components including a tread, a sidewall and the like. These components are provided with various appropriate properties. The tread which makes contact with the road surface needs to have wet grip performance and the like for safety and other reasons. A method has been proposed which improves these properties by addition of aluminum hydroxide. Unfortunately, this method deteriorates abrasion resistance and is thus rarely employed in the production of tires for general public roads. This method also has a problem in the processability of compounding materials.
Other methods are, for example, a method of increasing the styrene content or the vinyl content in solution-polymerized styrene-butadiene rubber, a method of using modified solution-polymerized styrene-butadiene rubber to control the tan δ curve, a method of increasing the amount of silica to provide a higher tan δ peak, a method of adding a liquid resin, and the like. At present, it is still difficult to improve wet grip performance while maintaining other physical properties.
Patent Literature 1 discloses the use of a specific rubber component and a specific inorganic reinforcing agent such as aluminum hydroxide to enhance wet grip performance, abrasion resistance, and processability. However, there is a need for further improvements.